WILLIAMSTOWN -- "The act of observing determines what is what," a Russian physicist tells a British intelligence officer early in Tom Stoppard's "Hapgood."

"The experimenter makes the choice. You get what you interrogate for."

On the surface, the physicist, Joseph Kerner, who defected from his native Russia years before the play's action begins, is talking about the seemingly contradictory properties of light. In truth, he is answering, in typically elliptical manner, a question about the condition of his loyalties.

"Joseph," the increasingly impatient M I5 officer, Paul Blair, says, "I want to know if you're ours or theirs, that's all."

Truth, like the properties of light, is what the observer makes of it; what others want an observer to make of it. Truth is the primary casualty in this dense, cumbersome play which is being given a dense, cumbersome production at Williamstown Theatre Festival's Nikos Stage.

Notions of what is true and not true, what is real and what is illusory are familiar thematic threads in Stoppard's writing.

Here the discussion is put in the service of a cloak-and-dagger-spy-vs.-spy drama that places at its center a working single mother, Elizabeth Hapgood (Kate Burton in the kind of go-for-broke self-assured performance that would hold the center of even a far more accomplished production of "Hapgood" than the one that surrounds her here). Hapgood is very good at what she does. At the same time, she has more than a few secrets of her own, among them the identity of her son's father.

The defecting physicist, Kerner (a physically awkward but by design emotionally restrained Jake Weber) is Hapgood's biggest achievement. Her success at turning him into a British agent after an extensive and exhausting period of interrogation made her career. But now, Hapgood and her boss, Blair (an unsteady, uncertain Reed Birney) are caught in a crisis. There's a double agent operating within their unit. To expose him, or her, they've constructed an elaborate series of charades. No one is whom they appear to be. Truth turns out to be as as malleable as light.

The stakes here are high, especially for Hapgood herself, as she balances her high professional standards on the one hand and protective devotion to her son on the other. Burton rises to this role as if Stoppard had tailored it just for her, including a transformation midway through that, initially at least, defies willing suspension of disbelief.

For all the endless reversals and melodramatic comings-and-goings, there is a love story at the heart of "Hapgood," two of them, in fact -- one between a mother and a son for whom she will go to any lengths to protect from the fallout of her work (it is no small deliciously wry irony that Hapgood's mission code name is "Mother"); the other between a mother and the father of her son. By necessity, one love gives way to the other. The price of that sacrifice also is at the center of "Hapgood."

But like so much in both the play and director Evan Yionoulis' production, the balances are often out of whack, as if Yionoulis isn't quite sure what to make of all this. The emotional dynamics among and between characters are rarely more than clinical at best. There are moments when then suspicion arises that Stoppard is having fun with his material at the audience's expense.

Determining what is what -- or why any of this should matter -- proves as elusive an exercise at the end of "Hapgood" as it seems at the beginning.

 

HAPGOOD by Tom Stoppard. Directed by Evan Yionoulis; scenic design, Christopher Barreca & Christopher Heilman; costume design, Michael Krass; lighting design, Donald Holden; sound design, Alex Neumann; original music, Mike Yionoulis; dialect and vocal coach, Deborah Hecht. Through July 21. Eves.: Tue.-Thu. 7:30; Fri., Sat. 8. Mats.: Thu., Sun. 2; Sat. 3:30. Williamstown Theatre Festival, Nikos Stage, ‘62 Center for Theatre and Dance, 1000 Main St., Williamstown. Tickets: $50. (413) 597-3400; wtfestival.org. 2 hours 28 minutes 

Wates Victor Williams

Russian Brady Dowad

Ridley Euan Morton

Kerner Jake Weber

Merryweather David Corenswet

Hapgood Kate Burton

Blair Reed Birney

Joe Adam Langdon

Maggs Sathya Sridharan